Protective device.



E. B. WEDMORE. PROTECTIVE DEVICE. APPLICATION TILED AUG. 19, 1909.

1,1 14,558, Patented Oct. 20, 1914.

3 SHEETS-SHEET 1.

6Q WITNESSES 1 INS/ENTER m k Km.

E. B. WEDMORE.

PROTECTIVE DEVICE.

APPLIUATION FILED AUG. 19, 1909. 1,1 14,558, Patented Oct. 20, 1914.

3 SHBETSSHEET 2.

INS/ENTER EDMUND .B. MDMUHE'.

W' twat,

F'igS E. B. WEDMORE. PROTECTIVE DEVICE. APPLICATION FILED AUG. 19, 1909.

1,1 14,558. Patented 001120, 1914.

3 SHEETS-SHEET 3. Fig.4

WITNESSES 6.21m.

, fiWENTUR EDMUND B.WEDML7RE', BY

H15 ATTURNEY unrrnn s'rnrns rarnnr @FFICE;

EDMUND n wnnmonn, for. nucrny, ENGLAND, JASSIGNOR r0 GENERAL 'nmiornio oomrany, aconromrron or new from;

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7 Specification of IzettersYateiit. Application-filed afi umba aoa. ESeriaLNo. 513,637.

' range of adjustment, and which will act.

instantaneouslyin case the abnormal conditions onthe'circuitito beprotected exceed predetermined limits.

In carrying out my .inventiomfthemechanism-is so constructed that :two cooperating members, such as the contacts of a relay,.- are brought .into definite rlation to: each other to open "the circuit to be protected. The mechanism "is "so arranged that the cooper ating members :or contacts approach each other as soon as the. abnormal conditions appear upon the circuit to be protectedgthe movement ofone of the :contacts being at a definite and predetermined rate,' while the movement of lithe other contact and S the position'assumed by it is dependent'uponathe conditionsin the circuit -to be protected. The cooperating inember or contact which moves at a predetermined rate may be 1 driven by clockwork or anyxsuitablemechanism which will give it a definite rate of movement unafiected -byithe current in-the circuit to be protected, while the other member or contact .is r actuated by 'any suitable electro+responsive device, such as a solenoid, theanovement of-ithe second member'bein-g controlled by somesuitablecontrolling or damping devicev such as a dash pot.

My invention 1 may best be understood :in connection with. the accompanying drawings, which show one of the various formsin which itmay be embodied and in'which ,Figure 1 is a fragmentary elevation, partly in section, of onei'embodlment of my invention in 1 the form of a three phase relay; Fig. 2 an end view ofthe relay shown in Fig. 1; Fig. '3 amodified fdrmof relay which is self restoring; Fig. 4 is: a diagram} matic illustration of a-relay havingnaither mostatic element; and Fig. his a diagnanr matic illustration :of a relay having as 'one' element san ammeter vmovement.

In th-e embodiment of ltheinvention shown in 'F :1;and;2, 'abaseor panel 1 is -provided with .a :support. 2 a and brackets 3 for holdinglrelay co1ls4, 5:and6,each of which is connected'tocne phase of aithree phase system. :Each coil is provided with an armature or l movable vplunger -7 which takes up. apositioniin the coil corresponding to the value of the currentflo wing throughthe coil and hence the movement and position of the plunger .7 of each-coil is dependent upon the conditionsiin' the :circuitto which the coils are connected. The movement "of 'eachplun- ,ger may be controlledin any suitable manner, and:in= the specific embodiment shown in the'drawings eachzplunger is controlled by 'meansiof a pistons carried'on a-rod 9 and slidingin -a%tube 10. Above'the plungers 7, a. tripping bar 111 is pivoted. at 112' to bnackets 13 mounted on-the base =1 .and when any or all 'ofith e plun ersrise, t eir' extremities .l i will engage wit 'aand'lift' the banll. .Mountedon, but insulated fromztheabar 11 is a projecting :member or contact ,l5 connected with the tripping circuit of 'the oil switch on othercircuit breakingdevice which controls the three phase system to xwhich the relay-coils4,"5 and 6 are connected. Directly above-the member-or contact 15 is mounted a cooperating :mcmber :or contact which is moved toward thecontact :15 at a definite and uniform rate and which engages the contactlo to closeithe tripping circuit and thereby 'causethe circuit breaking device to be operated. :In the specific embodiment shown inthe drawings, the contact: or member =wh-ichcooperates with 1 the contact :15 is made'in the'form-of a snail wheel 16 mounted upon a shaft .17 and insulated from the shaftby aninsullated collar 18-, said wheel l6ibein'g connectedwith the trippingci'rcuit and coiiperatingwith .the conta-ct 15. The shaft 17 carrying the-contactcr-snail wheel 16 is rotated at a definite. and uniform rate by 'any snitable driving mechanism, such as 'IPate'ntedOc't. 20,1914.

aclock with "an 'escapeme'nt, a fan, or similar device, the driving inechanism being snormally restrained by a l'u'g 1'7 mounted on the shaft 17 :to. engage a stop :11 onrthe' tripi ping bar 11. fThe lug 17 is released and the driving mechanism is set in action by the i same conditions which raise any of the! plungers 7. Where desired, a cover 19 may be placed over the operating parts of the relay to protect them, and ad ustable weights 20 may be secured by set screws 21 to the plungers 7 whereby each plunger may be set to begin its upward movement at any predetermined current value.

The operation of the protective device or relay shown in Figs. 1 and 2 is as follows: If it be assumed that the parts are adjusted so that the plu'ngers begin to rise at overload and the snail wheel contact 16 is in the position shown in Fig. 2, then when any one of the plungers rises, its extremity 14 engages the tripping bar 11 and lifts both the bar and the contact 15 upwardly into a position corresponding to the current value, while at the same time the stop 11 releases the lug 17 and leaves the shaft free to rotate. As soon as any plunger commences its upward movement, the driving mechanism begins to rotate the shaft 17 and snail wheel or contact 16 and as soon as the latter engages with the contact 15, the tripping circuit is closed and the main switch or circuit breaker automatically opened. At 50% overload, the plungers will rise only a little and the snail wheel would take a predetermined time, say five minutes, to come into engagement with the contact 15 and close the tripping circuit, but if the overload amounts to 100% the tripping bar is lifted higher and the time required for the snail wheel 16 to engage the contact 15 would be reduced to about two minutes, while if the overload reaches 300% the pull on the plunger 7 is so great that the dashpot has but little retardingefi'ect, and contact 15 will be lifted very quickly the snail Wheel 16.

In order to avoid the necessity of rewindinto engagement with ing a clock mechanism for driving the snail wheel 16 a meter movement may beemployed to drive the shaft 17 and may be operated from the bus bars. One form in which this. modification may be embodied is shown in Fig. 3, in which the relay mechanism'is substantially the same as shown in Figs. 1 and 2 and like parts are designated by like reference numerals. The rotating mechanism comprises a meter movement 22 which always runs at substantially the same uniform speed and is automatically set into operation upon the appearance of overload. Any overload which moves the tripping bar 11 closes the circuit through the meter movement by means of a spring contact 22 which engages a coiiperating contact as long as the tripping bar 11 is lifted out of normal position. A meter movement drives the contact or snail wheel 16 through a clutch, one

I member 23 of which is driven by the motor mechanism and engages with the other member 24 when the latter is thrown into mesh with the first member by means of a sole:

noid 25 provided with a movable core or plunger 26 which is rotatably and slidably mounted in holes in the projecting plates 27 and 28, the latter of which also supports the solenoid 25. One end of the plunger 26 carries the clutch member 24 and snail wheel 16, while the other end carries a grooved wheel 29 between which and the bearing 27 a spring 30 is arranged to normally hold the clutch members-apart. A cord 31 fixed to the wheel 29 is' attached to a weight 32 for rotating the plunger 26.

The operation is as follows: As soon as one of the plungers 7 rises the tripping bar 11 is likewise raised. Upon its initial movement this tripping bar closes the circuit through the meter movement 22 by means of the spring "contact 22. When the circuit has been so closed, the Lmeter movement 22 begins to rotate and the solenoid 25, being in series with. the meter movement, throws the clutch members into engagement, whereupon thesnail wheel or contact 16 is rotated and lifts the weight 32. Should theoverload cease before the tripping circuit is closed, the solenoid 25 is denergized, the spring 30 disengages the clutch members and the weight 32 returns the snail wheel or contact 16 to its original position.

. Although the invention --1s shown embodied in the form of a three phase relay,

it may equally well be employed on a single phase or polyphase system, and instead of the solenoid and plunger located in each phase of the circuit to be protected, I may use any suitable electro-responsive devlce, such as an ordinary ammeter movement or a thermostat, as long as the electro-responsive device has a moving part wh1ch assumes different positions in response to different current potential, or other electrical condition on the circuit to be protected. In

order to illustrate one of the many ways in which the device may be constructed to embody a thermostatic device, I have shown diagrammatically in Fig. 4 a local circult containing'a battery 33 or some other suitable source of current which is to be closed in accordance with the conditions on the main circuit 34. The circuit closing relay comprises the same driving mechanism as that shown in Figs. 1 and 2 and so connected that the local circuit is closed when the contact 15 engages the snail wheel 16. ,"The position of the contact 15 with relation to the snail wheel 16 is controlled by the thermostatic strip 35 comiected in series with the main circuit 34 and proportioned to bend upward as it is heated. A very slight upward movement of the thermostat 35 Wlll move the" stop 11? a sufficient distance to release the driving mechanism and start the snail wheel 16. The extent to which the snail wheel is turned before the local circuit is closed is determined by the position of the vto animus stop 15, which in turn is dependent upon the extent to which the thermostat -35 is bowed upward. I The invention may also be embodied the form of relay illustrated diagrammaticallin Fig. 5, in which the main circuit '34f1s connected to an anlri'iieter 36 provided with some sort of "control spring such as a spiral spring 87 preferably so proportioned that the ammeter has a suppressed zero and the moving element will turn against *the contrdl spring until the current reaches a predetermined limit. The moving "element of the ammeter carries an arm 38 and when the current of the main circuit ex ceeds the predetermined limit at which the moving element of the ammeter begins to turn, the position of {the arm is -"determined by the amount which the current in the main circuit exceeds the predetermined limit at which the movement began. The end of the. arm 38 controls the stop 1-1 of the driving-mechanism for the snail wheel 16 and the contact 15 is also carried upon the arm 38 so that the relation of the contact 15 to the snail wheel 16 is determined by and is dependent on the amount of current flowing in the main circuit. As soon as the arm 38 of the annneter is moved by a the excess'current the driving mechanism is released, the snail wheel 16 begins to rotate, and after a'period of time determined by the position of the arm 38 and the contact 15 the local circuit, including the battery 33,

' is closed.

While I have described one specific form of carrying out my invention, it will-be understood that many modifications may be made without departing from the spirit of my invention, and-I therefore do not wish to be restricted to the precise arrangement shown and-described, but intend'to cover by the appended claims all changes withinth'e spirit and scope of my invention.

What I claim as new and desire to secure by Let-ters'Patent of the United States, is,-

1. An inverse time limit overload relay comprising nonnally separated coiiperatingcontacts movable into engagement to'close the tripping-circuit, time actuated mechanism for moving said contacts toward each other at a definite and uniform rate when set in operation and means responsive to overload for instantaneously moving said contacts toward each other a distance de-/ pendent upon the extent of overload and for simultaneously rendering said time actuated mechanism operative to move said contacts-with a time lag over the remainder of the distance and thereby bring them into on gagement. 2. An inverse time limit overload relay for controlling a tripping circuit comprising cooperating contacts normally out of tripping relation, normally inoperative time actuated to close said ga i .ior moving said contacts from any position into tripping relation and means responsive to current in the circuit to be protected for instantaneously setting said contacts in such position that the extent to which they are out of circuit closing relation is dependent upon the amount of current and simultaneously rendering said time actuated mechanism operative to move said contacts from said position into tripping relation.

3. An inverse time limit overload relay comprising contacts normally separated to leave a gap in the tripping circuit, "a time limit actuating mechanism for closing the. 'gap between said contacts at a substantially "constant rate, and means responsive to overload for instantly rendering the gap between said contacts inversely proportional to the amount of overload and simulta- 1 neously starting said time limit mechanism at a predetermined rate which is indepen ent of the amount of overload.

tact members normally out o tripping relation, a current responsive device operatively related to one of said movable contact members for instantly moving it to render the extent to which said contact memhers are out of tripping relation inversely proportional to the extent to which the current in said device exceeds a predetermined amount, time limit actuating means for slowly moving said second contact member at a definite rate to bring said contact members into tripping relation, and means wherebysai-d-current responsive device in moving said first contact member simultaneously. renders said actuating means operativeto move said second contact member toward the first mentioned contact member.

5. An inverse time limit relay comprising relatively movable coiiperating contacts, 110

means for yieldingly holding said contacts separated, time limit actuating mechanism 1 for bringing said contacts into engagement at a definite and uniform-rate, and means ing said contacts toward each"otherto an extent dependent uponf-the amount of ov'e'rload and simultaneously rendering said time limit actuating mechanism operative to complete the closing movement of said contacts. 121) 6. An inverse time limit overload relay comprising two relatively movable c'odperating contact members, a current responsive demos for moving one of said contact memof overload, a'normally inoperative driving -mecl1anism"for moving said other contact member from an initial position toward the responsive to overload for instantlymov- 1T5 bers a distance proportional to the amount 125 device for setting said driving .mechanism' ber is returned to its initial position when,

the overload disappears.

7 A11 inverse time limit current responsive relay comprising a current responsive device, acontact member arranged to be actuated by said device when the current in said device exceeds a'predetermined amount, a rotatable contact member mounted to move into engagement with said first mentioned contact member, means controlled by said current responsive device for rotating sald rotatable contact member at a predetermined'uniform rate when the current in said device exceeds said predetermined amount, and'means tending to maintain said rotatable contact member in its initial position when the current in said current responsive device is less than said predetermined amount.

8. A time limit relay comprising a movably mounted contact for a tripping circuit, a time limit actuating mechanism comprising a movable cam shaped member and means for moving said member at a definite rate to complete the'tripping circuit through said contact, and means responsive to an abnormal condition on the circuit to be protected for moving said contact in a direction to close the tripping circuit and to an extent dependent upon the extent ofthe abnormal condition, and simultaneously setting said time limit actuating mechanism into operation to move said cam shaped member to close the tripping circuit.

9. A time limit relay comprising relatively movable cooperating contacts, one of which is provided with a cam surface and the other movably mounted to move from normal position toward said cam surface, time limit actuating mechanism for moving said first mentionedcontact at a definite rate to bring said cam surface and said other contact into engagement, and means responsive to an abnormal condition on the circuit to be protected for instantly moving said sec- 0nd contact toward the first a distance dependent upon the extent of said abnormal conditions and simultaneously setting said time limit mechanism into operation.

10. A time limit overload relay for an electric circuit comprising an electromagnet having a movable armature and responsive to current in saidcircuit, a movable contact member operatively related to said armature and adapted to assume a position proportional to the current in said circuit when said current exceeds a predetermined amount, a rotatable contact member in the form of a snail wheel, actuating means for rotating said rotatable contact member at a predetermined rate, means for setting said actuating means in operation when the current in said circuit. exceeds a predetermined amount and means for maintaining said rotatable contact member in an initial position when the current in said circuit is less than said predetermined amount,

' 11. A time limit overload relay comprising two cooperating relatively movable contact members, one of said members having a cam surface, the other of said members being mounted to move into* engagement with said cam surface, a time limit actuating mechanism for slowly moving said members relatively to each other to cause the high part of said cam surface and said cooperating contact member to approach each other at a predetermined rate, an electromagnet having a movable armature and responsive to current in the circuit to be protected, said armature being mounted to assume a posltion dependent upon the amount of overload and operatively related to one of said contact members to carry it toward said other contact member as said armature is moved by said electromagnet. I

12. A time limit overload relay comprising a rotatable contact member having a cam surface, an electromagnet having amovable armature and responsive to current in said circuit, a movable contact member operatively related to said armature and adapted to move toward said rotatable contact mem ber and in the plane of said cam surface a distance proportional to the overload in said circuit, a time limit actuating mechanism for slowly rotating said rotatable contact member at a predetermined rate, and means for setting said actuating mechanism in operation when'an overload occurs. I

13. A time limit overload relay for an electric circuit comprising, a rotatable contact member in the form of a cam, an electromagnet having a movable armature and responsive to current in said circuit, a movable contact member operativelyrelated to said armature and adapted to move toward the edge of said cam a distance inversely proportional to the amount of overload in said circuit and into engagement with said cam upon excessive overload, a time limit actuat ng mechanism for slowlyrotating said cam at a predetermined rate toward engagement with said movable contact, and means for setting said time limit actuating mechanismin operation when said overload occurs. let. A time limit relay for electric circuits comprismg an electromagnet having an armature, a movable contact member opera tively related to said armature, said movable contact member being arranged to move a distance proportional to'the current in said electromagnet when the current exceeds a predetermined amount, a rotating mechanism adapted to revolve at a predetermined rate, said mechanism being brought into opable contact member, and means whereby said snail wheel contact member is returned to an initial positiOn when the current through said rotating mechanism is less than 15 a predetermined amount.

In witness whereof, I have hereunto set my hand this tenth day of August, 1-909.

E. B. WEDMORE. Witnesses:

CHARLES H. FULLER, J. A. FOSTER. 

